Valve-gear



(No Model.) 2 SheetsSheet 1. N. W. TWISS.

VALVE GEAR.

No. 350,172. Patented Oct. 5, 1886.

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(No Model.) 2 Sheets-Sheet 2..

N. W. TWISS.

VALVE GEAR.

N0. 350,172. Patented Oct. 5,- 1886.

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ATTORNEY UNITED STATES PATENT OFFICE.

NELSON IV. TWISS, OF NE? HAVEN, CONNECTICUT.

VALVE-GEAR.

=JPBCIFICATION forming part of Letters Patent No. 350,172, dated October 5, 1886.

Application filed February 19, 1884. Serial No. 121,350. (No model.)

To all whom it may concern:

Be it known that I, NELsoN IV. Twiss, a citizen of the United States, residing at New Haven, in the county ol New Haven and State of Connecticut, have invented certain new and useful Improvements in Automatic Cut-0ffs for Steam-Engines, of which the following is a description.

My invention relates to cut-ott' mechanisms torsteam-engincs, and is an improvement upon an invention for which Letters Patentof the United States No. 212,285 were granted to me on the 11th day of February, 1879.

In the mechanism described in the patent referred to the cutoff valve was arranged within and concentric with an oscillating main valve, which turned in a cylindrical valvechamber. The cntolf valve was adapted to oscillate within the main valve, and had its stem or shal'tl passed axially th rough the hollow stem of the main valve. The cutoff valve was arranged to (lisengage from the driving-gear at the point of cut off and closed bythe action 01' a spring.

My present invention consists in a novelimproved closing device for operating the valve, as hereinafter more fully described, and pan ticularly pointed out in the claims.

In the accompanying drawings, Figure l is an end view of the valve stems and cranks fitted with my impror'ed closing device. Fig. 2 is a central vertical section through Fig. 1, and Fig. 3 shows the device with the inclosingcase omitted.

Referring to the drawings, L designates the cutoff-valve crank, and F denotes the main valve crank, which parts are fully described and shown in the patent referred to. A pin, a, is inserted in the face of the main-valve crank and projects through a slot, Z), in the cut-off-valve crank. A spiral spring, 0, is coiled loosely around the valve stem or shaft G, and is inclosed by a cylindrical cup or case, E, which is fastened upon the end of the shaft by means of a setscrew, (1. The setscrew passes radially through the cup near its closed end, and through an internal hub, 02, formed on the end of the cup around the shaft. The hub enters the end of the coiled spring, and a corresponding hub on the cutoff-valve crank enters the opposite end of the spring, by which means the coil is kept at a sufficient distance from the cut-oft-valve stem to allow it to contract. The spring is preferably wound so that its tension is in the direction to contract the coil diametrically. The outer end of the spring is bent parallel with the valve stem or shaft and adapted to bear against the set-screw d. The opposite end of the spring is hooked around the pin a, and when the case is prop erly adjusted on the val ve-stem the spring acts against the set.screw and the pin in the direction to turn the valvc-crank and close the cutoff valve. The end of the spring which bears against the set-screw may bearinstead against a suitable projection at the end of the cup, if desired. Any required tension may be given to the spring by turning the cup around on the stem in the direction to apply strain to the spring, and fastening it when adjusted by means of the set-screw d. The advantage of thisclosing device is, that it employs a spring which may be made of any required length and corresponding elasticity, that the spring is entirely incased and guarded by the cup or case, and that its tension may be easily regulated, as desired.

It is evident that the inclosing-case may be attached to the main-valve crank, or may be entirely dispensed with, if desired, in which case the hub a may have a projecting flange, k, formed upon it,with a slot, n, to receive the bent end of the spring 0, as shown in Fig. 3. \Vith this modification the tension ot'the spring is adjusted by turning the collar upon the shaft the same as the entire case is turned in the other form of the device.

I claim as new and desire to secure by Letters Patent- 1. In automatic valve gearing having an oscillating cut ot't valve within and concentric to the main valve, the combination, with the valve stems or shafts, of a spiral spring coiled around the cut-off-valve stem and arranged to act torsionally on the respective valve-stems and the cutoff valve, and a cup or case inclosing the spring and secured upon the cutoff-valve stem, substantially in the manner and for the purpose described.

2. The combination of the cutoff-valve stem or shaft G, the main-valve crank F, the cylindrical cup or case E, secured on the valvestem, and the spiral spring 0', inclosed within the case, coiled around the cut-off-valve stem, secured to the main-valve crank, and to act on the cutoff-valve stem in the direcact at one end torsionally on the main-valve crank, and an adjustable collar clamped upon adapted the cutoff-valve stem, and having a projection or abutment upon which the opposite end of 15 tion to close the valve, substantially in the the spring acts to close the valve, substantially manner described.

3. In automatic "valvegearing having an oscillating cut-0ft valve within and concentric to the main valve, the combination, with the valve stems or shafts, of a spiral spring coiled around the cutoff-valve stem and arranged to in the manner and for the purpose specified.

NELSON \V. TVVISS.

Witnesses:

GEORGE L. BARNES, J ULIUs TWIss. 

